


A Mistake

by Aria Serif (Mysterie)



Series: Tales From Yandereverse [5]
Category: Undertale (Video Game)
Language: English
Status: In-Progress
Published: 2020-06-11
Updated: 2020-06-11
Packaged: 2021-03-04 00:27:21
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 4
Words: 2,305
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24664600
Author URL: https://archiveofourown.org/users/Mysterie/pseuds/Aria%20Serif
Summary: As a guardian in training, Mika wants to prove she's ready to take the final step, but she is not prepared for what she will face ...
Series: Tales From Yandereverse [5]
Series URL: https://archiveofourown.org/series/1771984
Comments: 2





	1. Chapter 1

**Author's Note:**

> Sentinaltale, Aria, Mika (c) AGuardianOfDreams  
> Horrortale (c) Sour-Apple-Studios  
> Underlust (c) NSFWShamecave (tumblr)  
> Underswap (c) popcornpr1nce (tumblr)  
> Swapfell (c) Mod Sans (tumblr)

  
  


Mika stood in front of the portal, she was debating about what she was about to do. It wasn't like she didn't know anything about this place, but she had figured out how to open it. This multiverse was locked for a reason. She had heard warnings from her mother about it on several occasions. That the yandere multiverse was a dangerous place for even the most experienced of guardians and that she had locked it to keep others from just stumbling into it by accident and to keep most of the inhabitants inside. Of course that didn't mean that it was completely inaccessible. After all she'd seen her mother bring back some of the citizens from it a time or two. They were always shaken and relieved when they arrived with Aria, but Mika couldn't figure out why. They never talked of whatever world they came from or their family or really... much of anything about themselves.

Often they were sent to Underswap to recover, unless of course they came from Underswap, in which case Mika wasn't sure where her mother sent those to recuperate. She wasn't even sure WHAT it was they were getting over. Well, if her mother could come and go to the place surely it couldn't be that bad, right? Right. She could do this. She wasn't an official guardian yet but she wagered she only had another few years. She was sixteen now. Old enough that she'd braved Underlust, Horrortale and a host of others that were dangerous in their own right and done so alone and been fine. Surely this was going to be no different and on top of it, if she brought back someone too, like her mother did, then surely she would prove that she was ready to be an official guardian and for the final test.

  
  
Taking a deep breath, the young skeleton walked through the portal. 


	2. Chapter 2

**Summary for the Chapter:**

> Underfell (c) ???/ UT community

Where was she? The portal hadn't really shown her exactly where it lead as it was just that her magic had opened the last portal her mother had. Aria was resting, her brothers were out doing who knew what really and her father had left to speak with an Underfell counterpart. Honestly sometimes thinking about all the versions of Papyrus and Sans that were out there gave her a headache. Sometimes she wondered how there could be so many.... How did her mother keep track of it all anyway? It didn't seem to her like it was a job for just one single soul to do alone. Wasn't that the same reason the Council of Sanses had been formed in the first place? Well, then again her mother wasn't necessarily managing every place she kept track of so much as just gathering the information on them and passing it to the council. Why her mother answered to them without being one of them herself was another thing. Just one more mystery about her own mother that Mika had never thought to ask, but had in the back of her mind at times. Her mother could be a very strange skeleton, that much she was sure and sometimes Mika did not understand the motivation or reason behind some of the things that her own mother did or said. 

  
  
As she looked around though she was taking in everything she could. It was a snowy forest. Why was it ALWAYS a snowy forest? Seriously? Her mother dropped in Snowdin or snowy forests so very often. Too often, of course dropping into a town had its own issues but honestly, couldn't she just come out of an empty storage faculty or something once in a while? Mika felt the cold but seconds later a quick majik spell put an end to the cold air around her so she was comfortable despite wearing her usual green outfit that consisted of a long sleeved shirt, a pleated skirt, multicolored stockings, and a pair of pastel pink gloves. Her right eye light flickered a little between colors in her uncertainty, between the colors green and blue. It was the only eye light that changed colors, her other stayed a normal white and because of this many sometimes mistook her purple marking over her eye light to mean that there was something wrong with it, or that it was an injury of some sort because it didn't change color or anything like the other did. She'd even had one monster ask her if she was partially blind in that eye light. 

  
  
With an inward sigh she decided it would be best to try and ask the code where she was. She was about to when she heard a twig snap. She glanced around quickly.

  
  
"hello?" The silence greeted her back. Was it her imagination or was there someone there? She summoned her magic, just in case. A Guardian was supposed to be prepared for anything and that meant, of course, as well being ready to fight for life on a moment's notice.


	3. Chapter 3

**Summary for the Chapter:**

> Swapfell (c) Kkhoppang/ UT Community (adopted)  
> Undertale (c) Toby Fox

For a moment there was no sound then the sound of footsteps. She stood her ground, focused on the direction the footsteps came from and relaxed a hair when she saw the figure before her. A lanky, tall skeleton who wore a purple sweater with a black leather jacket over it and had a gold tooth; a nasty scar ran down his right socket but she knew who this was. One of the Swapfell brothers. She knew them. Though she wasn't sure which version this one was.

"heya. don't see other skeletons here often." 

"i imagine not. i'm a traveler." She knew better than to drop her guard completely in a fell world, but he seemed to not be hostile. He smirked a little, but there wasn't any hostility or malevolence in his stance. That was a good sign.   
"i'm a bit lost though. i've never been here before, perhaps you could help me?" 

"maybe." He walked towards her, she tensed a little until he stopped a few feet away only to hold his hand out.

"papyrus." 

"mika." She took his hand for a brief hand shake, ready to react if he tried anything funny, but he simply released her hand after the brief contact. This wasn't so bad. At least, not yet. Why had this place been locked away again? Surely she could handle anything that came her way. Still, she wasn't going to turn her back on this Papyrus until she could tell for certain if she could trust him or not. That was the problem with this verse... or so her mother had once warned.

*flashback*

_Aria paced a little before her daughter._

_"You have a genuine curiosity, but you should be very careful about applying that to the multiverses."_

_"why this one? why is it so dangerous?"_

_"Because it's unpredictable. The thing about it, even if you know every precaution to take against each type of dere in this place you have no way of knowing WHO it is. From timeline to timeline, world to world, it is different who develops it. It is often one of the skeleton brothers, but it is not a given. In swap verses it's usually the Sans... in tales and others... usually the Papyrus, but this is not a guarantee. I have seen others. Rescued Alphys... Undyne... Toriel... Gaster... Asriel... Chara... Everyone. At some point I have rescued at least one version of someone from their dere. Most often the yandere... but the others can be just as dangerous and believe me surviving an encounter with one is not something you want to add to your list of things you've done."_

*end* 


	4. Chapter 4

"hungry? i was just about to head home to make lunch." 

  
  
"i'd like that if you don't mind." 

  
  
"nah. i'm sure my brother will be happy to meet you too." 

  
  
"who is your brother?" 

  
  
"you don't know?" 

  
  
"well, i was taught not to assume since being a traveler you encounter all kinds." He chuckled a little.

  
  
"guess so. my brother is sans." 

  
  
"well, i'm sure it will be nice to meet him." Papyrus only smiled and she followed him to a house on the outskirts. She noticed that the streets were deserted. That was strange. There was no sign of dust so surely the human wasn't scaring everyone. Well, this was supposed to be a dere world right? Maybe it was just the dere who scared everyone... if that was the case then they were obviously not shy about hiding themselves. That could be a problem. Possibly, or it could mean they'd be very obvious and it'd be too easy to spot them and she'd have an easy time evading them. Either way, she recalled she'd always been taught to keep her guard up regardless of what type of world she was in.

  
  
As she followed him, she hoped that it was not his brother who was the dere... yet Papyrus did not seem to show any signs of being wary or afraid of his brother. Perhaps it was someone else? She knew she would need to be on guard as much as possible to try and figure out who it was before something made the dere act in a way she didn't want them to. Regardless of what kind of dere the soul was, most of them turned out to be very crafty and resourceful. That was why the tended to "rule the roost" as the saying went. 

  
  
The house Papyrus led her too looked like the Fells' house, if the Fells did everything in dulled colors and preferred purple and black to red and black. As she was led into the kitchen she began to wonder WHICH Swapfell she was in exactly. There were two distinct ones that were in separate multiverses and they were very much identical save for one very important key difference. The two brothers. She hadn't really learned to read code yet so she couldn't be sure and Papyrus hadn't given her his code name... thus she really couldn't be sure without Sans around. 

  
  
**BAM!**

  
  
Speaking of... 

  
  
"I HOPE YOU'RE NOT ASLEEP! IF YOU'RE ASLEEP AGAIN BROTHER I SWEAR I'M GOING TO- WHO THE HELL ARE YOU?!" 

  
  
"mika." She replied, the tiny tyrant-wannabe had stormed into the house like a whirlwind and was almost as loud as Undertale's Papyrus... almost. His voice had a deeper tone to it so it was second actually to Blue's loudness, Blue from Underswap being the loudest Sans she'd ever heard... but so far no one she'd met could top Captain. 

  
  
"hey bro, i was just about to fix lunch." 

  
  
"WHY ISN'T IT READY YET?! DIDN'T I SPECIFICALLY TELL YOU TO HAVE IT DONE WHEN I RETURNED?!" 

  
  
"yeah, but i ran into her on the way. you'll have to forgive the delay this one time, m'lord." Well this wasn't helping... just who were they exactly?

  
  
"FINE. THIS BETTER NOT HAPPEN AGAIN MUTT OR SO HELP ME..." Ah! There it was.

  
  
"it won't happen again." 

  
  
"IT BETTER NOT!" He turned from his brother back to her.  
"JUST WHO ARE YOU? I'VE NEVER SEEN YOU BEFORE." 

  
  
"i'm a traveler, that's why. i don't do it often so that's probably why you've not seen me before." He frowned.

  
  
"WHERE ARE YOU FROM?" 

  
  
"you probably wouldn't believe me if i told you." 

  
  
"TRY ME! I'VE BEEN EVERYWHERE!" Mika considered if she should tell the truth or lie. She glanced over at Mutt but he wasn't paying attention. He wasn't going to be any help.  
"WELL?!?" 

  
  
"it's a rather isolated place, it's called the anti-void." She replied after a moment with a shrug. A glance in Mutt's direction told her the other was tensing slightly. _Well if you didn't want me to be honest you should have thrown me a bone here._

  
  
"ANTI-VOID? WHAT KIND OF PLACE IS THAT? I'VE NEVER HEARD OF SUCH A PLACE!" 

  
  
"hmm, like i said, it's pretty isolated. it's not a place you can reach just by walking there. it takes very specific magic to get there, well, more to the point you have to know the magic that is required to get there." 

  
  
"WHY?"

  
  
"you know... i don't know that one. i haven't been told why." 

  
  
"FIGURES, YOU'RE JUST A KID." 

  
  
"not wrong there." She wasn't going to argue with him or point out that she was a kid who could probably kick his butt, that wouldn't be smart to say. She might be young but she wasn't stupid and she didn't really want to tangle with a fell of any kind. 

  
  
"ARE YOU JOINING US FOR DINNER?" 

  
  
"yes, your brother was kind enough to ask." Sans nodded thoughtfully.

  
  
"LET'S GO TO THE DINNING ROOM WHILE HE COOKS!" There was a dining room? She followed him out, she didn't recall the Fells having a dining room. It was only when she saw another door that was near the stairs did she wonder how she missed the extra room. Well, she hadn't really gotten that good of a look at the place she supposed. She followed him inside and there she saw a long table with various chairs. It was so long that it could have probably fit all the most well known monsters along it. Sans took a seat at one end, it was the only end that actually had a chair. The other end didn't have one and she had a feeling it was likely because he fancied himself the most important in the home. She took a seat to his left, seeing as she assumed that Mutt likely sat at the right, Sans didn't say anything on it so she assumed she was likely right. Now, what could she say to break the silence between her and her host? When he gave her a very small smile she felt a bit of a chill. Was he... ? 


End file.
